The June Heat is On and Our “Monsoon Season” is Just Around the Corner!

Weather Talk

POSTED: Friday, May 30, 2014 - 10:55pm

UPDATED: Friday, May 30, 2014 - 11:26pm

Upper level high pressure produces record breaking 100º+ temperatures next week and we kick off our monsoon season June 15th

Next week the National Weather Service kicks off their "Monsoon Awareness Week". Every day I will cover a different topic associated with weather safety, such as floods, lightning and even extreme heat. The Borderland is entering our hottest month of the year, June. El Paso average high is 95.5º for the month with most of our average 15.4  yearly average of 100º days happens during this month. The high temperatures will be near or above the century mark Sunday through the Thursday next week. Is it too early to be thinking about our wettest time of the year, “monsoon season”? In today’s “Weather Talk” I will take a look at where the Borderland gets its moisture during monsoon season, from when to when does El Paso see the most average rainfall and what impact El Niño might have this year.

The National Weather Service decided a few years ago to start the Borderlands monsoon season at the same time Phoenix, Arizona from June 15th through September 30th.

The Borderland and our region, Southern New Mexico and Far West Texas, see most of our monsoon moisture come from the Gulf of Mexico. We also catch the edge of second source Pacific moisture from the Baja of California to our west. During our summer monsoon season our region frequently experiences showers and thunderstorms with sometimes heavy rainfall. This is due to the seasonal changes in the circulation across the southwestern United States. Usually in late June or early July, the prevailing dry westerly flow retreats northward as warm surface temperatures create a broad area of low pressure at the surface across southern California, western Arizona and northwestern Mexico. This feature often referred to as the "desert heat low” pulls moisture northward from the Gulf of California or Gulf of Mexico into the Southwest. There is also a third weaker source of humid air flowing right over Mexico from the Pacific south of the Yucatan Peninsula that we can sometime tap into.

El Paso sees most of our 9.43”average annual rainfall, about 5.56” of it, during the monsoon season from June 15th through September 30th. Here is a monthly breakdown of El Paso’s monthly average rainfall from just before to just after our monsoon season;
              EL PASO
Monthly Average Rainfall
MAY                      .47”
JUNE                    .94”
JULY                  1.55”
AUGUST            2.01”
OCTOBER          .61”

The months of June, July, August and September is when we see the most thunderstorms, rainy days and most of our rainfall.
Most people do not think we receive much rain in June because of our amount of 100º days and some years we do not. On average we do have a few good, soaking storms rumble through during the month of June.

Will El Niño help boost our monsoonal rain and thunderstorm activity?

First “El Niño” happens along the west coast of South America. This is where the cool Peru Current is swept northward and these southerly winds promote upwelling of cold, nutrient rich water that gives rise to a large fish population. Fish like Anchovies thrive attracting a large population of sea birds. The sea bird droppings are phosphate rich and are called “guano” which supports a big fertilizer industry. Near the end of each calendar year, a warm current of nutrient poor water pushes southward, replacing the cold, nutrient rich surface water. Because this normally happens around the Christmas season, the local residents called it “El Niño”, Spanish for child, referring to the Christ child. During most years the warming of the surface water only happens for a few weeks to a little over a month. Then the weather patterns return to normal and the fishing gets better. When El Niño conditions last for many months, there is more extensive heating of the surface water causing a dramatic economic impact locally but evaporation more moisture into the air. During a strong El Niño many fish, birds and marine plants die. This leads to bacteria production, heating the surface water even more. This extra moisture is picked up by the trade winds which are swept into the southern Jet stream and carried our way.

Should the El Niño form, meteorologists suggest it may bring badly needed rain to the western and southwestern U.S..

The National Oceanic and Atmospheric Administration’s (NOAA) latest El Niño summer prediction is good. In the NOAA Climatic Prediction Center’s May 8th update the say;
The Northern Hemisphere is “most likely transitioning to El Niño during the summer. There remains uncertainty as to exactly when El Niño will develop and an even greater uncertainty as to how strong it may become. This uncertainty is related to the inherently lower forecast skill of the models for forecasts made in the spring. They go on to say “the chance of El Niño increases during the remainder of the year, exceeding 65% during the summer.”

This should help increase the number of late day thunderstorms and rainy days during our summer monsoon if the El Niño.

The western, southwestern U.S.. as well as Texas and the southern central plains states are in desperate need of a good rainy season. The extra rainfall will help agriculture, livestock and greatly reduce our extreme fir danger. Next week I will cover topics, like lightning, Flash Flooding and more that are associated with monsoon season. I do not like seeing the damage and tragedy of some of the severe thunderstorms that are produced by extra moisture, but I would love to see some of the long overdue, well needed benefits of extra rainfall.

Chuck DeBroder, Chief Meteorologist
KTSM, NewsChannel 9, NBC, El Paso, TX

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